EXTRALIMITAL RECORD Herald Petrel new to the West Indies Michael Gochfeld,Joanna Burger, Jorge Saliva, and Deborah Gochfeld (Pterodroma)are bestrepresented SinA southGROUP temperate THEGADFLY and subantarc-PETRELS tic waterswith a few speciesbreeding on tropicalislands in the Central Pacific, Atlantic, and Indian Oceans.In the West Indies,the only member of this genusis the Black-cappedPetrel (P hasitata), which breeds in the Greater Antilles and perhaps still in the Lesser Antilles. A dose relative,the endangeredBermuda (P..cahow) breeds in Bermuda. On July 12, 1986, while studyingthe breeding Laughing Gulls (Larus atri- cilia), Royal Terns,and SandwichTerns (Sterna maxima and S. sandvicensis)on Cayo Lobito, in the Culebra National Wildlife Refuge, about 40 kilometers eastof Fajardo,Puerto Rico, we flushed an all-dark petrel from a scrapeamong the nestingterns. As soon as the bird wheeled around we realized that it was a petrel, and not the familiar Sooty Shearwater(Puj•nus griseus),a species Figure 1. Dark-phasePterodroma landing among Laughing Gulls on Cayo Lobito. Culebra, which would itselfbe extremelyunusual PuertoRico. Note the ashygray undersurface of theprimary.feathers, ending in longnarrow at Culebra. Compared to a shearwater, "digital" extensionsthat are the pale areas of the inner websof theprimaries. The greater the petrelappeared to havea largerhead underwingcoverts are pale with a narrowdark tip that showsas thefaint wavybar at the base of theprimaries. The Iongishtail and shortishbill are apparent. and a longerand slightlywedge-shaped tail. It did not showthe conspicuouspale wing linings of the Sooty Shearwater (Fig. 1). The bird circled rapidly, first low over the water and then wheeling high overthe rocky islet,before return- ing to its scrapeamong the gulls and terns. At this point, we studied it at a distance of 15 meters and noted its short, stout black bill, with the promi- nent tubes(Fig. 2), which,with its char- acteristicshape or "jizz" and rapid, er- ratic, wheelingflight, identified it as a Pterodroma. 1254 American Birds, Winter 1988 When the bird was flushedagain it out that in the Pacific the Herald Petrel circled and was chasedby a Laughing (P. a. heraldica) is widely sympatric Gull, which provided a good size com- with the Kermadec Petrel, indicating parisonby revealingits slightlysmaller that the two are distinct species.Palmer size(Fig. 3). Size eliminatedthe much (1962) arguedthat they are besttreated smaller Bulwer's Petrel (Bulweria bul- as a superspecies,the positionfollowed weriO, which has been recordedfrom by the A. O. U. Check-listCommittee the Gulf of Mexico (Taylor 1972) and (A. O. U. 1983). southernCaribbean, and alsothe larger Procellaria petrels.We now faced the Exclusionof most otherpetrel species task of sortingamong a variety of dark forms of Pterodroma. Firstly we narrow the identification We watched and photographedthe to two closelyrelated species,the Ker- petrel for about 30 minutes. It circled madec Petrel and the Herald Petrel, Figure 2. The Pterodromasitting on scrape us at closerange, and landedback in the basedon the followingcharacters. in a colonyof gullsand ternson CayoLobito. samescrape three times.We ascertained Note the all-dark head and short, stout black that its bill and legswere entirely black, 1) Size and all dark color bill. The one whitish spot on the upper wing therebyeliminating several species, and 2) Absenceof white featberingon head is and wasnoted occasionally in flight. The that therewas no hint of palefeathering 3) Color of softparts pale line alongthe folded lefl wingmay be a on the face,a fact that eliminatedseveral 4) Nestinghabits photographicartifact that was not noted in thefield nor in other photographs.Alterna- others. In the field we discerned that al- tively,it may be a pale featherj?om the un- though there was no contrastingwhite Size and all dark color dersideof the wing, whichis revealedas the wing patch, the primary region of the wing wasbeing extended. wing was distinctly paler than the dark Many Pterodroma speciesare poly- underwing coverts, a feature shown morphic, with light, intermediate,and 90-110 centimeters, we find that vir- clearlyin Figure 1. dark phases.Our examination of spec- tuallyall Pterodromaspecies with a dark Although field identificationof Pter- imens suggeststhat someof thesespe- phase, except the larger Great-winged odroma petrels is often uncertain, we des are probably not polymorphic at Petrel (P. macroptera)and smallerand were fortunate in being on terra firma all, but showcomplete gradation from rare Fiji or MacGillivray's Petrel (P. rather than on a pitching boat, and birds with all white to nearly all dark macgillivrayi), fall within this range. having the petrel circle us and land re- underparts(see illustrations in Murphy Thus size servesmainly to eliminate peatedly within 15 meters. After ex- and Pennoyer 1952). However, rela- speciesin other genera. amining relevant speciesaccounts in tively few of the dark phasesare com- Harrison (1983), we focusedour atten- pletely dark. Some dark Pterodroma Absenceof White Featheringon Head tion on the Herald or South Trinidade petrelscan be eliminated on the basis (P. arminjoniana) and Kermadec (P. of a distinctivepattern; among theseis Among the Pterodroma specieswith neglecta)petrels. After examinatingthe the Kerguelen Petrel (P. brevirostris), an all-dark phase,most regularly show extensivepetrel collectionin the Amer- which has a pale leading edge to the some white feathering on the head, ican Museum of Natural History, we wing. Many spedesshow a pale areaon lores, throat, or chin, or at the base of have identified this bird as an all-dark the head, throat, lower abdomen, or the bill. Many dark specimensofP. ar- phaseof the SouthTrinidade Petrel, the rump. Table I summarizesfeatures of minjoniana and almost all P. neglecta first record,albeit only photographic,of the dark-bodiedpetrels in Pterodroma have such feathering,but some of the the speciesfor the West Indies. There and related genera (after Hardson former showno white feathering.This follows a detailed discussion of the basis 1983).Species of Pterodromanot listed absenceof an area of white feathering for our conclusion. in Table I are those with no known dark helpsrule out Solander'sand Murphy's phase. petrels(P. solandriand P. ultima). The latter, believed by Murphy and Pen- Taxonomy The Culebra petrel was slightly shorter-bodiedand longer-wingedthan noyer (1952) to be closely related to The Trindade Petrel (P. arminjon- a Laughing Gull for which Hardson iana sensustricto) and the Herald Petrel (1983) givesa body lengthof 40 centi- Figure3. The dark Pterodromabeing chased (P. heraldica)of the Pacific, are cur- metersand a wing span of 103 centi- by LaughingGull. Note the slightlysmaller bodyand longerwings of thepetrel. The long, rently treated as a singlespecies, called meters. It is readily apparent that the slightlywedge-shaped tail is prominent. the Herald Petrel, P. arminjoniana all-dark Bulweria petrels are much (Murphy and Pennoyer 1952; A. O. U. smaller and the all-dark Procellaria pe- 1983; Hardson 1983). Although Mur- trels are much larger than the bird in phy (1936) consideredP. a. arminjon- question. The Puffinus shearwaters, iana as an Atlantic representativeof the several of which are dark-bodied, are Kermadec Petrel (P. neglecta) and mostly larger (except lherminieri and stated that possibly"it should be re- nativitatis)than the Culebrapetrel, and gardedas a subspeciesof the latter", and differ also in bill shape, tail shape, and Hellmayr and Conover(1948) actually flightbehavior. lumped arminjoniana with neglecta. Acceptinga body sizein the rangeof Murphy and Pennoyer(1952) pointed 34-40 centimetersand a wing span of Volume 42, Number 5 both neglectaand armmjomana, Is a must be invoked to balance the prob- 1961,see below) it would be premature Pacific specieswhich otherwise could abilities. There are two resident species to exclude that specieson the basis of easilybe mistaken for the Culebra bird. of Pterodroma in the West Indies area range.Based on the A. O. U. Check-hst (if one includesBermuda), both of them (1983) the only otherPterodroma petrel blackishabove and mostly white below. recorded in the northwestern Atlantic Color of softparts Both are rare, and neither has been re- is a singlespecimen of the Mottled Pe- We were able to watch the Culebra cordedin the Culebra region. The Ca- trel (P. inexpectata),a light-bodiedspe- how breeds only in Bermuda, has a cies,taken in New York in 1880. Even petrelat closerange as it sat on its scrape and as it lowered its feet to land. The world populationof lessthan 100 pairs, thoughit breedsin the EasternAtlantic and has no known dark phase. Range and has a rarely collecteddark phase, bill and legs and feet were obviously alone would not exclude it, but rarity the Soft-plumagedPetrel (P. mollis)can blackish, without a hint of flesh or and patterncertainly would. The Black- be excluded because of its dark mask bluishcoloration. Murphy (1936) notes capped Petrel breeds on some of the and white wing patches. The Great- that pale and intermediatephases of the Greater Antilles and perhaps still on winged Petrel could be expectedin the South Trinidade Petrel have pale or some Lesser Antillean islands. It has western Atlantic, but can be excluded two-toned tarsi and feet. This two-toned never been known to breed on Puerto on the basis of size. appearanceis characteristicof the Pa- Rico, but range and rarity are not suf- There are several dark-phase Ptero- cific form P. a. heraldicain all phases, ficient to exclude it. Moreover, there droma petrelsthat are not known from of intermediate-phase P. a. arminjon- was a well-known dark phase of this the Atlantic, but that neverthelessmust lana, and also apparently of dark-phase species, the "Jamaican" or "Blue be considered. Solander's Petrel could neglecta.However, our examination of Mountain" Petrel (P. hasitata carib- certainly be confusedwith dark arrmn- A.M.N.H. specimensreveals that the baea), which bred on Jamaicaat least joniana, except for the distinctlypale light phaseas well as the dark phasesof until the end of the 19th century (Scott cast to its breast and chin.